This invention relates to a method of and apparatus for wrapping units to be wrapped, and more particularly to a method of and apparatus for wrapping units such as reams of paper each in a wrapper constituted by a sheet of wrapping material such as paper.
The invention has been especially developed for wrapping reams of paper, and particularly reams of paper such as are supplied for use in copying machines, in a wrapper constituted by a sheet of paper or other suitable wrapping material. It will be understood that a ream generally comprises a stack of five hundred sheets of the paper, the sheets being 81/2".times.11" or 81/2" by 14" sheets, for example.
The invention is generally in the same field as the method and apparatus disclosed in the coassigned U.S. Pat. No. 3,861,120 issued Jan. 21, 1975, entitled Wrapping Apparatus and may be regarded as involving improvements thereover.
Wrapping such reams of paper and especially wrapping them at a relatively high production rate (e.g., 80-90 per minute) presents special problems due to the difficulty in maintaining the integrity of the ream (i.e., maintaining the ream with all the sheets in register) and due in many instances to the flexibility of the ream as a whole and the resultant tendency of the ream to sag during the wrapping operation, with resultant distortion of the wrapped package. Also, it has not heretofore been practical, particularly with the apparatus shown in U.S. Pat. No. 3,861,120, to produce wrapped reams with the bottom seam of the wrapper extending endwise of the ream in a generally centralized position between the sides of the ream, as is desirable, rather than being closely adjacent one side of the ream. Also, for high speed wrapping, it is desirable to start each wrapping cycle (the cycle of operations involved in wrapping one ream) before the preceding cycle has been completed, and this has heretofore presented a problem.